gobsmack

Hi Guys, I need help here. All my A6 C5 1999 model injectors are leaking petrol. I have changed O-rings three times now. the leak seems to be coming from the top of the injectors and it looks to be getting worse. Could it be that my fuel pump is pushing too much petrol that injectors connate accommodate? or perhaps the injectors are old considering the age of the vehicle. Or has this got anything to with the ECU readings?
I'm planning to buy one injector, fit it and see it will leak, just so I can be certain that the problem is with the injectors and not the O-rings.
Your quick response will be highly appreciated.

Thanks!

Airbag

for all of the injectors to be all of a sudden leaking fuel is not right .. unless there is more to the story. I also doubt it would be quantitly of fuel delivered by the pump . i would verify fuel pressure however and suspect fuel pressure regulator or return line to the tank. i think before doing anything though I would verify that pressure. if it is in spec then look closely at injectors or fuel rail.

SloopJohnB@mac.com

I assume you're posting about the O rings between the injectors and the fuel rail. If new O-rings aren't stopping the leak(s) I have to assume you either have bad O-rings (did you buy them from the dealer?) or something has gone wrong with the injectors or the fuel rail…how did these multiple leaks start? Did you just alluvasudden notice fuel leaks one day (lucky sod you didn't burn up your/in your car!) or did the leaks 'happen' when you put the engine back together from some maintenance or repair procedure?

Sounds more like a bent/damaged fuel rail or fuel rail/injector interface. Or the wrong O-ring. Or improperly installed fuel rail or injector. Try again.

gobsmack

Thanks for the responses Airbag and Sloop. Well, I bought all 12O-rings new from the dealer, cleaned the engines holes thoroughly, lubricated the O-rings and fitted them twice, well, (I can say this is my third time doing this procedure cos the very first time only two injectors were leaking). When it happened the first time, I just had a fuel smell and I checked and saw the leak from one injector. I will check if the Fuel Pressure is according to spec.
My engine was never removed or had vigorous dismantling since I had this beautiful baby. I'm not driving the care at the moment. it looks like a fire risk.

gobsmack

What would be the proper spec or Bar for the Fuel Pressure Regulator?

Airbag

I don't have a Bentley but I'm sure someone here will know fuel pressure. Why did you change the parts the very first time?

SloopJohnB@mac.com

So..are they leaking now? If you put in new O-rings and it still leaks there's something wrong with the fuel rail or the injector(s). Swap the leaking injector to another position that isn't currently leaking and see if it leaks there. If it still leaks in the new position it's the injector…if the swapped injector leaks it's the fuel rail.

gobsmack

Initially, i had a problem with only one injector leaking. I changed the O-ring for that particular one. The injector with new O-rings was cool and fixed but, the others started leaking. I then bought 12 O-rings to fit on all injectors. It did not help and they are all leaking.

SloopJohnB@mac.com

OOOOKAY. It's possible but unlikely the dealer gave you the wrong O-rings…they should pretty much match the ones you have or be slightly larger in thickness. Otherwise, you boogered the fuel rail or the injector(s) or didn't get the fuel rails on all the way. End of story. When you replaced one O-ring and it fixed the problem but generated others on the same rail…that should have told you something. Then you repeated it when you took all the fuel rails off and replaced the O-Rings and all the rails leaked. See where I'm going with this? Harsh, but logical...

SloopJohnB@mac.com

I've come across 43.5psi at idle for the 2.7T. I suspect that's with the intake manifold pressure signal disconnected (connected, the fuel pressure might be less but I don't know). There is some connection to the info below, probably use the below information:

Here's some more from an old 2011 post…
Bentley A6 Service Manual - Fuel pressure specs

2.7L and all V8 idling, gauge connected inline bet. fuel rail and fuel suply line.
-Fuel pressure regulator vacuum line connected = 3.5 bar (51 psi)
-Fuel pressure regulator vacuum line disconnected = 4.0 bar (58 psi)

Residual pressure, leave gauge conencted, shut off engine, wait 10 mins
-Warm engine = 3.0 bar (44 psi)
-Cold engine = 2.5 bar (36 psi)